Interested to Buy Any Domain ? << Click Here >> for more details...
what is private constructor?what are the uses of writing
private constructor in our program?
- 10 Answers
- 21724 Views
- I also Faced
- E-Mail Answers
Answer Posted / poonam suryawanshi
When we create a private constructor, we cannot create
object of the class directly from a client. So we will use
private constructor when we do not want instances of the
class to be created by any external client. Even it does not
allow us to inheritance of the class in another class.
Example Utility functions in project will have no instance
and be used without creating instance, as creating instances
of the class would be waste of time. When we create the
Private Constructor we have to make all the Variables and
Function as static.
| Is This Answer Correct ? | 6 Yes | 3 No |
Post New Answer View All Answers
What is a priority queue java?
What is java regex?
What is a method in coding?
Difference between serialization and deserialization in java?
Give a practical example of singleton class usage?
What are green threads in java?
What is equlas() and hashcode() contract in java? Where does it used?
How will you call an Applet using Java Script Function?
Why generics are used in java?
How many bits is a 64 bit byte?
How many ways can an argument be passed to a subroutine and explain them?
What are the drawbacks of singleton class?
Can private class be extended java?
What are the drawbacks of reflection?
The following program reads data (details of students) from a file named students.txt and converts it into e-mail addresses. The results are written to a file named studentemail.txt. students.txt consists of a number of lines, each containing the data of a student in colon delimited format: Last Name:First Name:Student Number Each input record is converted to an e-mail address and written to studentemail.txt in the following format: the first character of the last name + the first character of the first name + the last four digits of the student number + “@myunisa.ac.za” import java.io.*; public class EmailConverter { public static void main(String[] args) throws IOException { BufferedReader input = new BufferedReader(new FileReader ("students.txt")); PrintWriter output = new PrintWriter(new FileWriter ("studentemail.txt")); String line = input.readLine(); while (line != null) { // Extract the information for each student String[] items = line.split(":"); // Generate the email address String email = "" + items[0].charAt(0) + items[1].charAt(0) + items[2].substring(4,8) + "@myunisa.ac.za"; email = email.toLowerCase(); // Output output.println(email); line = input.readLine(); } input.close(); output.close(); } } Rewrite the class so that it handles possible errors that may occur. In particular, it should do the following: • It should catch at least three appropriate exceptions that might occur, and display suitable messages. • At this stage, the program will not run correctly if there is an empty line in the input file. Change the program so that if an empty line is encountered, an exception is thrown and the empty line is ignored. This exception should be handled with the display of a suitable error message. • Before the e-mail address is added to the output file, check if the student number has 8 digits. If not, throw an InvalidFormatException (which the program should not handle itself)
